A World to Explore

Archive for September, 2015

Paul Taylor (Natural History Museum, London) is, along with his other talents, an expert on the folklore of fossils. His accounts of how fossils have been used and imagined in the past are fascinating, especially to paleontologists who work with them every day. (We had an example this summer at Whitby, England, with Saint Hilda and the ammonites.) So I was primed when Tim Palmer told me about an article on “Lapis Judaicus” or “Jews’ Stone” by Christopher Duffin (2006). Tim thought the medicinal value of these things was particularly appropriate for me.

At the top of this post is a clavate (club-shaped) spine from the echinoidPseudocidaris. I collected it years ago from the Matmor Formation (Middle Jurassic, Callovian) exposed in Makhtesh Gadol, southern Israel. In classical and medieval times this would have been a Jews’ stone (or jewstone). Its shape is critical, of course, but also its provenance in the Middle East.This is an illustration from Gesner (1565) showing a set of Jews’ stones (taken from Duffin, 2006, fig. 2). The image on the right (“.3”) is very close to our Pseudocidaris spine. The range of shapes for Jews’ stones was broad; all simply had to have this general clavate appearance and be from the Holy Lands.

Jews’ stones are examples of a kind of sympathetic magic attached to natural objects. It was thought that the globular shape of these spines resembled a bladder, and so these stones could be used to treat urinary disorders of various kinds. Sometimes the ancient prescriptions called for them to be sucked, but more often the stones were ground into a powder and combined with other exotic ingredients for consumption either orally … or other ways. The Jews’ stones were thought to have both preventative value as well as curative.

And that is why Tim recommended them to me. One of their primary uses was for the cursed kidney stones.

Nice to know I could have a potential treatment available right there on the outcrop!

BRYN MAWR, PENNSYLVANIA–When we last saw Mae Kemsley (’16) and Meredith Mann (’16) in this blog, they were celebrating the end of their Senior Independent Study summer fieldwork on the coast of North Yorkshire, England. This weekend the three of us traveled to Bryn Mawr College and the geochemistry lab of Professor Pedro Marenco to start the geochemical analysis phase of our research. We learned a lot under Pedro’s kind and generous direction.

Both Mae and Meredith have belemnite fossils in their field collections. Meredith has just a few from the Passage Beds Member of the Coralline Oolite Formation (Upper Jurassic, Oxfordian); Mae has dozens from the Speeton Clay (Lower Cretaceous). A belemnite was a marine squid-like cephalopod that had a hard, bullet-shaped internal structure called a guard (shown above). These guards are made of almost pure calcite which took in trace elements from the seawater as they grew. The carbon and oxygen isotopes in their calcite crystals also reflect the isotopic composition of the seawater. These fossils are thus geochemical repositories from ancient seas. We are interested in what our belemnites tell us about the ambient chemical conditions in their environments, which in turn are proxies we can use to interpret paleotemperatures and other factors.

In our Wooster geology labs we cut small disks from a series of belemnites, then polished the surfaces and cleaned them thoroughly. We brought these prepared disks to Pedro’s lab in Bryn Mawr.

Mae is here in the Bryn Mawr petrography lab using a small drill to excavate fine calcite powder from the belemnite disks. This powder, measured in fractions of a gram, was then collected into sheets of weighing paper, folded like origami and taped to keep it in place.

Mae and Meredith are here weighing the powder samples with Pedro’s fancy balances. Each plastic sample vial had to be paced through an ion generator to reduce static charge and improve measurements to the microgram. A lot of chemwipes, weighing sheets, and gloves are used in the process to reduce contamination.

After dissolving the powder samples in acid, and then diluting the liquids in carefully-measured ways, we finally ended up with these precious tubes filled with essence de belemnite. We learned how much work goes into preparation of geochemistry samples — a lot!

The liquid samples are now ready for analysis in a device called an ICP-MS, which stands for Inductively Coupled Plasma Mass Spectrometer. This is the process and equipment Wooster geologists Mary Reinthal (’16) and Chloe Wallace (’17) described in their recent geochemistry blogpost. We’re doing the same thing: assessing the trace elements in our samples. Pedro will later run our samples through this magic machine and give us the results. We have a duplicate set of drilled belemnite powders to send to another lab for carbon and oxygen isotope analysis.

This post is in honor of Yael Leshno, a graduate student at The Hebrew University of Jerusalem who is beginning her dissertation on the Middle Jurassic marine fossils of Israel. I’m proud to be on her committee. She will have some fascinating material to work with, and she has great ideas to test. This will be a fun and productive project.

Among the Jurassic groups Yael will concentrate on are the calcareous sponges. This is ambitious because they are poorly known and the literature is replete with outdated names and concepts. Her work will be of great value, though, because sponges can tell us a lot about the environments in which they flourished. They may also give us much needed information on the biogeographical context of the Jurassic faunas of the Middle East.

Above are four sponges from the Matmor Formation (Callovian, Middle Jurassic) of Makhtesh Gadol, southern Israel. These types of sponge are fun because they actually look like sponges with their porous exteriors and central osculum (excurrent hole). They are the least complicated type of fossil sponge. (Yael will see plenty of the challenging ones!)In this closer view of one of the Matmor sponges you can see the complex spicular network of the exterior (the structure that held the living cells). You will also note near the base the coiled tube of a sabellid worm named Glomerula gordialis (Schlotheim, 1820).Here is a top view looking into the osculum of the largest specimen. Sponges are filter-feeders, sucking in water through their exterior pores, filtering the organic material out, and then sending the used water out an osculum like this.

This sponge type is traditionally named Peronidella Hinde, 1893; it would be then placed within the Family Peronidellidae WU, 1991. I’m suspicious of this name because it used for sponges from the Devonian through the Cretaceous, so it is likely a form-genus (meaning a named form that may not have particular systematic value). Yael will no doubt section these common Matmor sponges and find enough internal detail to come up with a more useful name.George Jennings Hinde (1839-1918; image from Woodward, 1918) named the fossil sponge genus Peronidella in 1893. Hinde grew up in a farming family in Norwich, England. He was clearly a self-starter, studying classical languages and science on his own as a boy. When he was about 16 he listened to a lecture given by a clergyman on the Scottish geological polymath Hugh Miller (1802-1856), who had recently died tragically. Hinde was intrigued and began to explore geology. In 1862, after beginning his own farming, Hinde visited the geological collection at the British Museum in London. He began an acquaintance there with a family relative, the famous geologist and paleontologist Henry Woodward (1832-1921). In that same year Hinde sold his farm and moved to Argentina to raise sheep. A few years later he traveled to North America and began an epic seven years studying geology, traveling across the eastern half of the continent. (He must have had a considerable source of income for this!) He enrolled as a student in Toronto University under the paleontologist H.A. Nicholson (1844–1899) and began to produce his first geological papers. When he returned to England in 1874 he was elected a Fellow of the Geological Society of London. He continued to travel, this time over much of Europe and the Middle East. In 1880 he finished his PhD under Professor Karl Alfred Ritter von Zittel (1839-1904). He had a long career after that with numerous papers and scientific awards. Long et al. (2003) adds to this biography that Hinde very much wanted women to be allowed membership in the Geological Society of London, a point neglected in the obituary by Henry Woodward (1918). Hinde did not, alas, live to see the success of his progressive quest. The first woman was elected a Fellow of the GSL on May 21, 1919, a little more than a year after his death.

References:

Hinde, G.J. 1893. A monograph of the British fossil sponges, Part III. Sponges of the Jurassic strata, p. 189-254. The Palaeontographical Society, London.

In five days, three Wooster geologists prepped and analyzed over 50 samples, ate tons of food, and learned a lot of science. Okay, maybe not tons of food, but we did eat a lot. For three solid days, rising junior Chloe Wallace and rising senior Mary Reinthal were able to dabble in wet chemistry at the Ohio State University under the guidance and supervision of Dr. Pollock. The days were spent in geochemistry labs preparing sieved whole rock samples for ICP-MS analyses.

For those not familiar, ICP-MS stands for Inductively Coupled Plasma-Mass Spectrometer. ICP-MS is a system that allowed us to determine trace elements in our samples, which better help us separate lithofacies units into distinctive geochemical groups. This, then, allows for a broader understanding of how and when these units were emplaced in relationship to one another. That’s a lot of information from some geochemistry.

Chloe and Mary in the clean lab.

One of the days, Chloe and Mary were able to get outside and venture around campus and check out some of the sights. But most days at OSU main campus were spent not in the sun, but in the basement, measuring solutions, precisely weighing powders, wearing clean-lab gear, or inputting data into the computer.

Chloe weighing whole-rock powders.

Mary pipetting acids into the vials to digest the samples.

After long days of work, however, we got to peruse the campus scene, and we ate somewhere new every day. It was exhausting work, but the hope is for some good data.

At this time of the year I pick out one interesting specimen from the fossils my Invertebrate Paleontology class collected on their first field trip into the Upper Ordovician of southern Ohio. They did so well this week that I may be choosing a few more later! Our Fossil of the Week is the above bryozoan given the beautiful name Constellaria polystomella Nicholson, 1875. It was found by Jacob Nowell at the Caesar Creek Emergency Spillway in the Liberty Formation.Constellaria is a beautiful form, and one of the easiest bryozoans to recognize. Like all bryozooans, it was a colonial invertebrate with hundreds of filter-feeding individuals (zooids) housed in tiny tubes called zooecia. In Constellaria some of the zooecia are regularly grouped together and raised into star-shaped bumps called monticules. (The name Constellaria is clever.) This genus is a cystoporate bryozoan in the Family Constellariidae.I was surprised to learn that Constellaria was named in 1846 by James Dwight Dana (1813-1895), one of the most accomplished American scientists of the 19th Century. He is best known for his Manual of Mineralogy (1848) which is still in print (greatly revised) and known as “Dana’s Mineralogy”. Dana (shown above in 1858) studied geology on scales from crystal structures to continents, with volcanoes and mountain-building in between. He had an affinity for “Zoophytes” (animals that appear to be plants), thus entangled him briefly with bryozoan systematics. Dana was born in Utica, New York, and attended Yale College, working under Benjamin Silliman, a famous chemist and mineralogist. After graduating from college he had a cool job teaching midshipmen in the US Navy, sailing through the Mediterranean in the process. For four years he served in the United States Exploring Expedition in the Pacific region. He made numerous important geological observations in Hawaii and the Pacific Northwest that he later published in books and papers. He even dabbled in theology with books like Science and the Bible: A Review of the Six Days of Creation (1856). Dana died in 1895 having received numerous accolades and awards for his research and writing.

Many of our students enjoy a semester or year abroad during their college time. Andrew Wayrynen ’17 is right now in New Zealand, one of the favorite destinations of Wooster geologists. He has generously shared some of his recent geological images with this blog. The striking section above is part of the “Pancake Rocks“, which are exposed on the west coast of the South Island of New Zealand near the village of Punakaiki. This is an Oligocene limestone that has been diagenetically altered by compaction and eroded into steep-sided shapes by freshwater dissolution and marine influence.What looks like bedding in the Punakaiki Limestone is actually the effect of dissolution of the carbonate caused by immense overburden. One of our favorite Wooster geologists, structural guru George Davis, has a recent paper on this process (Davis, G.H. 2014. Quasi-flexural folding of pseudo-bedding. Geological Society of America Bulletin 126: 680-701.)Andrew also visited the Moeraki Boulders on the Otago coast of the South Island. These are large spherical concretions weathered out of a Paleocene mudstone known as the Moeraki Formation.

These are septarian concretions, a type characterized by a three-dimensional network of mineral-filled cracks, as shown in Andrew’s image above.

Like the liberally-educated geologist he is, Andrew did not neglect to show the marine organisms encrusting some of the intertidal boulders. These, of course, are barnacles.

And finally, here is Andrew, happily seated on a Moeraki Boulder in a geologist’s paradise!

Ohio is a wonderful place for paleontologists. One of the reasons is the thick, productive set of Upper Ordovician rocks that are exposed in the southwest of the state in and around Cincinnati. It is an easy drive south from Wooster into some of the most fossiliferous sediments in the world. Today Wooster’s Invertebrate Paleontology class went to Caesar Creek Lake in Warren County with its shoreline and emergency spillway exposing richly productive limestones and shales of the Waynesville, Liberty and Whitewater Formations (all of which equal the Bull Fork Formation). I’ve been there many times with many classes. The weather today was hot and dry — a contrast with last year’s torrential rains and mud.

After a three-hour drive, we stopped first at the U.S. Army Corps of Engineers visitor center for Caesar Creek Lake. The Corps built the dam and spillway for the lake, and continues to maintain them both. This center has a set of museum displays and is where we obtain our fossil collecting permit. (This image was taken by Mara Sheban, a sophomore at The College of Wooster who will be contributing photographs to this blog and other geology projects.)

Our initial briefing, with a review of the local geology and most common fossils. Since this is the start of the Invertebrate Paleontology course, most students have only begun to explore the topic. The fossils they collect on this trip will be the basis of a semester-long project of systematics and paleoecological analysis. (Photo by Mara Sheban.)

Our march to the far north of the exposures at the Caesar Creek Lake emergency spillway. We actually drop down from the spillway to the lake’s south shore. (See photo at the top of this post.) In the distant parking lot you can just make out a white pick-up truck in which the seasonal ranger is keeping an eye on us.

Jacob Nowell collecting small fossils washed from the shale along the lakeshore. (Photo by Mara Sheban.)

Jacob Pries found a nice enrolled Flexicalymene trilobite. Caesar Creek has a reputation as being a good place to find trilobites. We love them, but are also interested in the rest of the fossil fauna. (Mara Sheban image.)

Some of the limestone units are a nearly solid hash of cemented brachiopod shells.

My favorite slabs at Caesar Creek Lake are the abundant carbonate hardgrounds like the above. A hardground is a cemented seafloor, usually with borings and encrusting organisms. This one began as a burrowed soft carbonate sediment. The burrows were filled with fine mud that cemented early on the seafloor. The surrounding softer matrix washed away, leaving a hardground with the burrows now in positive relief. Brachiopods and corals then lived in the nooks and crannies of this hard rock on the bottom of the sea.

Here is the burrow system in a closer view. In the upper right is a beautiful encrusted rugose coral, shown in detail below.

That coral is almost completely covered by a trepostome bryozoan. I would have loved to collect this specimen for further study, but the slab is too large and no tools are allowed on this outcrop.

The Wooster Geology Department has started the 2015-2016 school year during beautiful late summer weather. Above is the traditional first-of-the-year image of the Geology Club. Everybody is happy to be a geologist.

Here are 12 of our senior geology majors this year. Trevor Shoemaker ’16 is missing. Adam Silverstein ’16 was a minute late for the photo, but we’ll give him special prominence below:

All of our seniors collected field and laboratory data for their Senior Independent Study projects over the summer, as you’ve read in this blog, and are already starting their analyses and writing. It is going to be a great IS year.

Here is the geology faculty. Left to right are Greg Wiles, Shelley Judge, Meagen Pollock, Mark Wilson, and Caitlin Current. (I must be standing on a root or something — I’m not that much taller!)

One of the first paleontology labs involves “picking” microfossils (mostly foraminiferans) from sediment samples. This is the Tuesday lab section hard at work.

Shelley Judge’s Structural Geology course got outside in the first week to learn how to use the essential Brunton Compass. The students have a series of angled boards here as part of an exercise to improve their accuracy and measurement speed.

I couldn’t get a good time to photograph Meagen Pollock’s Mineralogy lecture and lab, nor her large Geology of Natural Hazards class. Shelley Judge is also teaching for the first time her new course titled “Geology of National Parks”. Greg Wiles is teaching a section of Environmental Geology, as is Caitlin Current. This year I’m the department’s contribution to teaching the First-Year Seminar course. My section is titled “Nonsense (and why it’s so popular)“.

In the office we have our essential Administrative Coordinator Patrice Reeder (on the left), with her assistant this semester, Alexandra Gustafson (a senior Philosophy major). They manage both the Geology and Philosophy Departments, as well as the Pre-Law program.

Throughout the building, and often in the field, we all benefit from the tremendous skills of our Geological Technician, Nick Wiesenberg.

Here’s to another great year of geological education, research and outreach!

At the beginning of my Invertebrate Paleontology course I give each student a fossil to identify by whatever means necessary. I challenge them to take it down to the species level, and tell me its age and likely place of collection. The fossil this year is shown above: the rugose coral Stereolasma rectum (Hall, 1843) from the Middle Devonian of New York. I collected the specimens on my western New York adventure last month from the Wanakah Shale Member of the Ludlowville Formation at Buffalo Creek in Erie County. (There were a lot of them! This coral is so common that you can buy them online at science supply stores.)

The corals I collected were well weathered on the Devonian seafloor. You can see some evidence of this in the exterior which shows opened tunnels of borings. They were not appreciably weathered on the outcrop because they were directly excavated from the shale matrix.This is a cross-section through one of the S. rectum specimens. The internal radiating calcitic partitions (septa) are well preserved by clear calcite cement. There appear to be at least two generations of sediment that penetrated into the interior after the death of the polyp. The posthumous events affecting these corals may be more interesting than their life histories.

That awkward species name comes from the Latin rectus for “straight”. The anatomical rectum that we all know well comes from the same root but is based on a misconception by early anatomists that the terminal part of the large intestine in mammals is straight. It’s not, as a Google search will quickly show you. (I decided against including an image.)References:

Baird, G.C. and Brett, C.E. 1983. Regional variation and paleontology of two coral beds in the Middle Devonian Hamilton Group of Western New York. Journal of Paleontology 57: 417-446.